Kidde Optical Smoke Alarm is a compact and simple smoke alarm with a non-replaceable, sealed-in Lithium battery for 10 years of continuous protection – meaning the user never needs to change the battery for the full duration of the alarm’s life. This compact and versatile unit is easy to install and can be used anywhere in the home, particularly bedrooms, living rooms and hallways, with the added convenience of never having to change the battery.